A technique to set the target turning vehicle speed when the vehicle travels the corner based on the radius information of the corner in front of the vehicle is known. For example, Japanese Patent Application Laid-open No. H10-184903 (Patent Document 1) discloses the technique to detect node data from a navigation system device to obtain a node radius for each node, obtain a recommended travel speed in each node from the node radius, set a deceleration curve for each node, and determine an optimal gear position suitable for decelerating to the recommended travel speed from the deceleration curve.
Patent Document 1: Japanese Patent Application Laid-open No. H10-184903